Public address system



1, 1939- L. KAMENAROVIC 3 PUBLIC ADDRESS SYSTEM Filed April 6, 1938 Patented Aug. 1, 1939 PATENT OFFICE PUBLIC ADDRESS SYSTEM Leone Kamenarovi, Milan, Italy, assignor t Fabbrica Italiana Magneti Marelli Societa Anonima, Milan, Italy,

a corporation of Italy Application April 6, 1938, Serial No. 200,537 In Italy April 9, 1937 9 Claims (Cl. 179--1) This invention relates to public address systems adapted for generating or reproducing sounds and diilfusing them to public, and has for its object a portable apparatusincluding means for generatts ing sounds, means for amplifying them and means for diffusing amplified sounds all such means being able-to be enclosed when in conditions for transportation within a container having an exceedingly reduced over-all size and of the kind of hand-portable luggage; the apparatus of this invention also includes means for fastening the devices thereof in said container to'prevent them being subject to harmful movements during transportation. an embodiment of this invention is illustrated by way of example on the annexed drawing and ig. l a general perspective view of the appa--- rates with the container in open condition and the various units providing said apparatus arranged therein;

3 is a transverse section on line 3-3 of Fig. 4 illustrates a detail in transverse section on -line 4-4 of Fig. 2;

'Fig. 5 is a transverse section on line 5-5 of so Fig. 2;

'Fig. 6 is a front view of a unit of the apparatus in operative conditions;

Fig. 7 is a fragmentary side view to an enlarged scale. of the top portion of the unit shown in 35 Fi Fig. 8 is a fragmentary side view of Fig. 7 from right hand in the direction of the arrow.

' As shown in the drawing, the apparatus includes two main units A and B which are adapted to be 40 located. adjacent to each other in a container C when in conditions for transportation said container having a lid C hinged to the container body C and a handle C".

The unit A includes a casing l enclosing a loud- 45 speaker 2 with attendant parts and the unit B includes an electron-tube amplifier denoted in its whole by 3; said units A and B are adapted to be located adjacent to each other within the con tainer C as shown in Figure 1 for transportation, 50 and they are removed from said container and located in appropriate spaced locations for use.

The casing I of the unit A provides chambers t having shutters 5 at their top ends; the space within chambers 4 is in communication with the 66 space encircling the rear or outer surface of the loud-speaker cone or diaphragm 2 through ports 6 provided in a partition l8 separating said chambers 4 from the space 19 in which said loudspeaker is located (Fig. 4)

The chambers 4 are availed of to enclose acces- 5 sory or attendant parts of the apparatus, as a microphone and connecting wires or cables (not shown) when the apparatus is arranged for transportation, said shutters 3 being then closed. At

the time the apparatus is set for operation the content of chambers 4 is removed therefrom and the shutters 5 are then left open, said chambers t being then operative as resonators for the loud speaker to provide for an efiicient reproduction of low notes or tones, as well known.

"in front of the mouth oi the loudspeaker cone 2 two lids "5 are hinged at M at a. distance from the cone mouth to confine a space adapted to contain a turn-plate l of a phonograph belonging to the unit B as hereinafter described, said turn 20 plate ii being removed from the phonograph and located in said space iii when the apparatus is put in conditions for transportation; also disk shaped phonograph records (not shown) may be located in space. 2.5

The casing I is confined by walls H, H, H" on its side intended to lie adjacent to unit B when said units are arrangedadjacent to each other within the container C for transportation; said walls H, H, H" provide a depression 8, 8' adapted to receive parts extending from the unit B said units thus compenetrating each other in part to reduce the overall size of their assembly and of the container C intended to enclose it.

The unit B which includesthe electronic-tube amplifier 3 includes a casing 22 in which the parts of said amplifier 3 are located and also an electric motor 16 intended to drive the phonograph record turn-plate l5 when said turn plate is nested on the shaft N5 of motor I 6 which extends outside of casing 2!; the casing 22 also provides a space for location of attendant parts as connecting cable.

On the outside of the Wall 26 of casing 22 from which the motor l6 depends into said casing, a support 23 is fastened which carries a tone arm 16 having a pick-up 24 adapted to scan the phonograph record located on and operated by the motor shaft 15'; said wall also carries means for controlling the circuit of the motor it as shown conventionally at 25.

To hold the pick-up or tone arm in stationary when inoperative, a tail l4 extends from said arm and engages in a slot l3 of a bracket i2 fast on the top wall 26 of casing 22; as shownin Figures '7 5 and 8, said slot I3 is preferably somewhat inclined to secure the engagement of the tail l4 therein.

When the apparatus is to be put in condition for operation, the units A and B are removed from the container C and located each in appropriate location and position.

The lids I and shutters 5 of the unit A are carried in open position, the turn plate I5 is removed from space 2| and the content of the chambers 4 is removed therefrom; then the unit A is located in erected position as shown in Fig. 4, on a suitable stand of any kind. The unit B is located in erected position as shown in Fig. 6, the turn plate I5 is fastened in position on the motor spindle l6 and the pick-up arm I is released from its fastener I! for cooperation with a phonograph record located on said turn plate I5. Finally the electric circuits of the two units A and B are interconnected by connecting wires or cables and the apparatus is operated in conventional manner.

To pack up the apparatus for transportation purposes, the connecting cables are removed and located in chambers 4 and H, the turn plate l is removed from shaft I 6' and located in space 2| of unit A where also phonograph records may be stored, if any, the pick-up arm i0 is carried and engaged in inoperative position as shown in Figures "7 and 8 with its tail [4 engaged in slot l3, lids I and shutters 5 are closed and the unit A is located over that B as shown in Fig. 3 the parts I ll, l6 and 25 of unit B thus fitting within the depressions 8, 8 of unit A whose confining walls engage said pick up arm Hi and prevent it from moving transversely while it is prevented by cooperating means i2, i3, M from moving towards or away from the top wall 26 of the unit B; finally the assembly of said units is located and enclosed within the container C whose lid C is then closed and thus the apparatus may be carried by its handle C" as a conventional hand luggage.

ill/hat I claim as my invention and desire to secure by United States Letters Patent is:

1. In a portable public address system, a container, a block-shaped unit including a loudspeaker and adapted to occupy a portion of the space within said container, a second blockshaped unit including an electron tube amplifier and adapted to occupy the remaining space in said container and outer parts carried by one of said block-shaped units and projecting from its face intended to be adjacent to a face of said second named unit when said units are located within said container, the face of said second named unit intended to be adjacent to said first named unit when said units are located in said container providing recesses adapted to receive said projecting parts.

2.. In a portable public address system, a container, a block-shaped unit including a loudspeaker and adapted to occupy a portion of the space within said containerfa second blockshaped unit including an electron tube amplifier and adapted to occupy the remaining space in said container and outer movable parts carried by one of said block-shaped units and projecting from its face intended to be adjacent to a face of said second named unit when said units are located within said container, the face of said second named unit intended to be adjacent to said first named unit when said units are located in said container providing recesses adapted to receive' and engage said projecting parts.

3. In a portable public address system, a container, a block-shaped unit including a loudspeaker and adapted to occupy a portion of the space within said container, a block-shaped unit including an electron tube amplifier and adapted to occupythe remaining space in said container, a phonograph record scanning pick-up arm mounted on the outside of said second named unit on a wall thereof intended to be adjacent to a faceof said first named unit when said units are located within said container, the face of the said second named unit intended to be adjacent to said first named unit when said units are located in said container providing a depression for reception and engagement of said pick-up arm.

4. In a portable public address system, a container, 'a block-shaped unit including a loudspeaker and adapted to occupy a portion of the space within said container, a block-shaped unit including an electron tube amplifier and adapted ,to occupy the remaining space in said container, a phonograph record scanning pick-up arm mounted on the outside of said second named unit on a wall thereof intended to be adjacent to a face of said first named unit when said units are located within said container, cooperating means on said wall and on said pick-up arm for engagement thereof, the face of the said.second named unit intended tobe adjacent to said first named unit when said units are located in saidcontainer providing a depression for reception and engagement of said pick-up arm.

5. In a portable public address system a container, a block-shaped unit including a loudspeaker and adapted to occupy a portion of the space within said container, a block-shaped unitr including an electron tube amplifier and adapted to -occupy the remaining space in said container, Ta. phonograph record scanning pick-up arm mounted on the outside. of said second named unitv on a wall thereof intended to be adjacent to a face of said first named unit when said units are located within said container, a part fast on said second unit wall and having a slot substantially parallel with said wall of said second unit and an extension on said pick-up arm for engagement with said slot, the face of the said second named unit intended to be adjacent to said first named unit when said-units are located in said container providing a depression for reception and engagement of said pick-up arm.

6. In a portable public address system, a container,-a block -shaped unit adapted to occupy a portion of thespace within said container, said unit including a loud-speaker and providing spaces adjacent to said loud-speaker, said spaces having orifices opening to the outside of said unit and being adapted to contain attendant parts and to act as acoustic resonators for said loudspeaker when operated, removable shutters for closing said orifices or leaving them open at will, and a second block-shaped unit including an electron tube amplifier and adapted to occupy the remaining space in said container.

7. In a portable public address system, a container, a block-shaped unit adapted to occupy a portion 'of the space within said container, said unit including a loud-speaker and providing spaces adjacent to said loud-speaker and adapted to contain attendant parts and toact as acoustic resonators for said loud-speaker when operated, a second block-shaped unit including an electron tube amplifier and adapted to occupy the remaining space in said container, and outer parts carried by one of said block-shaped units and projecting from its face intended to be adjacent to a face of the other one of said units when said units are located within said container, the

face of the said second named unit intended to be adjacent to said first unit when said units are located in said container providing recesses adapted to receive said projecting parts.

8. In a portable public address system, a container, a block-shaped unit adapted to occupy a portion of the space within said container, a loud-speaker in said unit, a partition at the rear of said loud-speaker separating a room in said unit at the rear of said loud-speaker and means in said unit providing other spaces adapted to contain attendant parts and to act as acoustic resonators for said loud-speaker when operated, said partition and means having perforations for intercommunication of said room and spaces, and a. second block-shaped unit including an,electron tube amplifier and adapted to occupy the remaining space in said container.

9. In a portable public address system, a container, a block-shaped unit including a loud speaker and adapted to occupy a portion of the 

